A surgical suturing system comprises a shaft having a proximal end, a distal end, a longitudinal axis between the proximal and distal ends, and receiver on the distal end with a rotary drive. A cartridge is selectively attachable to and detachable from the receiver. The cartridge has a surgical needle, a length of suture connected to the needle, a needle driver operative to engage and move the needle relative the cartridge, a transmission operatively connected to the needle driver, and a torsional interface rotationally coupling the rotary drive to the transmission.